SlabParameters

Scheme constants of the WRF 5-layer slab (thermal diffusion) land-surface scheme, transcribed from the module parameters and in-line literals of phys/module_sf_slab.F (WRF 4.8, SUBROUTINE SLAB1D). Mounted by the slab component as subsystem `par` so that no tuning constant is written inline in the physics. Values are the nominal (decimal) values of the Fortran source; the WRF build evaluates them in single precision.

Domain: land_surface
Subdomain: slab
Type: model
.esm schema: 1.0.0
Source: components/land_surface/slab/slab_parameters.esm
Tags: #land_surface #slab #model #wrf #land-surface #scheme-constants

Description

Scheme constants of the WRF 5-layer slab (thermal diffusion) land-surface scheme, transcribed from the module parameters and in-line literals of phys/module_sf_slab.F (WRF 4.8, SUBROUTINE SLAB1D). Mounted by the slab component as subsystem par so that no tuning constant is written inline in the physics. Values are the nominal (decimal) values of the Fortran source; the WRF build evaluates them in single precision.

Reference

Dudhia, J. (1996). A multi-layer soil temperature model for MM5. Preprints, 6th PSU/NCAR Mesoscale Model Users’ Workshop, Boulder, CO, 49-50.
Blackadar, A. K. (1978). Modeling pollutant transfer during daytime convection. Preprints, 4th Symp. on Atmospheric Turbulence, Diffusion and Air Quality, Reno, NV, AMS, 443-447.
wrf-model/WRF v4.8.0 phys/module_sf_slab.F (DIFSL, SOILFAC, SLAB1D literals).

Parameters

Name	Units	Default	Description
`difsl`	`m^2/s`	`5e-07`	Soil thermal diffusivity DIFSL, uniform over the column (module parameter).
`soilfac`	`1`	`1.25`	Safety factor SOILFAC on the explicit soil sub-step count, nsoil = 1 + floor(4 soilfac difsl dt / dzs(1)^2). Only the Fortran time stepping reads it; the instantaneous-tendency form of the component does not.
`capg_per_thc`	`Jcms^0.5/(cal*m^3)`	`59114000.0`	Volumetric soil heat capacity per unit thermal inertia for the multi-layer soil, CAPG = 5.9114e7 THC (J K^-1 m^-3 per cal cm^-1 K^-1 s^-1/2), chosen so that capg sqrt(difsl) reproduces the thermal inertia THC.
`capg_per_thc_single`	`Jcms^0.5/(cal*m^3)`	`3298000.0`	The same coefficient for the one-layer (force-restore) form of the scheme, CAPG = 3.298e6 THC; recorded for completeness, the multi-layer component does not use it.
`hm_coef`	`1/rad`	`1.18`	Force-restore coefficient of the deep-soil restoring term HM = 1.18 eomeg (TG - TMN) of the one-layer form; the multi-layer form computes HM but does not apply it. Per radian, so that hm_coef eomeg (eomeg in rad/s) is a rate in 1/s.
`t_snowmelt`	`K`	`273.16`	Cap on the ground temperature under snow cover when IFSNOW = 1 (SLAB1D literal 273.16).
`land_water_threshold`	`1`	`1.5`	XLAND threshold separating land (1) from water (2) points; the scheme changes only land points.
`kpa_per_pa`	`kPa/Pa`	`0.001`	Unit conversion applied to the surface pressure before the Bolton/Tetens saturation formula, whose prefactor svp1 is in kPa (SLAB1D: PSFC = PSFCPA/1000).

Raw .esm

Raw .esm JSON (this component)

{
  "variables": {
    "difsl": {
      "type": "parameter",
      "units": "m^2/s",
      "default": 5e-07,
      "description": "Soil thermal diffusivity DIFSL, uniform over the column (module parameter)."
    },
    "soilfac": {
      "type": "parameter",
      "units": "1",
      "default": 1.25,
      "description": "Safety factor SOILFAC on the explicit soil sub-step count, nsoil = 1 + floor(4 soilfac difsl dt / dzs(1)^2). Only the Fortran time stepping reads it; the instantaneous-tendency form of the component does not."
    },
    "capg_per_thc": {
      "type": "parameter",
      "units": "J*cm*s^0.5/(cal*m^3)",
      "default": 59114000.0,
      "description": "Volumetric soil heat capacity per unit thermal inertia for the multi-layer soil, CAPG = 5.9114e7 THC (J K^-1 m^-3 per cal cm^-1 K^-1 s^-1/2), chosen so that capg sqrt(difsl) reproduces the thermal inertia THC."
    },
    "capg_per_thc_single": {
      "type": "parameter",
      "units": "J*cm*s^0.5/(cal*m^3)",
      "default": 3298000.0,
      "description": "The same coefficient for the one-layer (force-restore) form of the scheme, CAPG = 3.298e6 THC; recorded for completeness, the multi-layer component does not use it."
    },
    "hm_coef": {
      "type": "parameter",
      "units": "1/rad",
      "default": 1.18,
      "description": "Force-restore coefficient of the deep-soil restoring term HM = 1.18 eomeg (TG - TMN) of the one-layer form; the multi-layer form computes HM but does not apply it. Per radian, so that hm_coef eomeg (eomeg in rad/s) is a rate in 1/s."
    },
    "t_snowmelt": {
      "type": "parameter",
      "units": "K",
      "default": 273.16,
      "description": "Cap on the ground temperature under snow cover when IFSNOW = 1 (SLAB1D literal 273.16)."
    },
    "land_water_threshold": {
      "type": "parameter",
      "units": "1",
      "default": 1.5,
      "description": "XLAND threshold separating land (1) from water (2) points; the scheme changes only land points."
    },
    "kpa_per_pa": {
      "type": "parameter",
      "units": "kPa/Pa",
      "default": 0.001,
      "description": "Unit conversion applied to the surface pressure before the Bolton/Tetens saturation formula, whose prefactor svp1 is in kPa (SLAB1D: PSFC = PSFCPA/1000)."
    }
  },
  "equations": [],
  "tests": []
}